What causes premature birth? What are the immediate health issues of the baby?
Recently, my friend delivered her baby early, at 32 weeks gestation by caesarean section. Fortunately, the delivery was uneventful and both mum and child are well. I would like to know the causes of premature birth and the immediate health issues of the baby.
A normal pregnancy usually lasts 40 weeks. Premature birth is one that occurs before 37 weeks of gestation and happens in about 10 %of all pregnancies. Depending on how early the birth occurs, it is further subdivided into:
• extremely premature (earlier than28 weeks)
• very premature (28 to 32 weeks)
• moderate to late premature (32 to 37 weeks).
Very often, no specific cause of premature birth can be found. However, there are factors that may be associated with premature birth. These include:
· Intrauterine infection of the membranes and/or amniotic fluid that surround the baby. It is estimated that the infection is associated with about 40% of premature births
· Excessive amniotic fluid as found in gestational diabetes and multiple pregnancies e.g. twins and triplets.
· Hypertension during pregnancy, in which Caesarean section or induction of birth has to be done early for medical reasons
· Chronic medical conditions in the mother e.g. kidney failure, heart disease and diabetes mellitus.
· Teenage pregnancies
· Laxity of the neck of the womb (cervix) resulting from repeated abortions or surgery to the cervix
· Structural abnormalities of the womb (uterus) e.g. uterine septum, double womb
· History of a previous premature birth
· Poor nutrition
Understandably, premature birth gives the baby less time to develop in the womb. Premature babies, especially those born very early, will have organs that tend to be less developed, which make them more prone to complicated medical problems. They can also become ill fast, when a mild condition can suddenly deteriorate and prove fatal.
Not all premature babies experience complications. Generally, the earlier a baby is born, the higher the risk of complications.
Life-threatening complications include:
· Respiratory distress syndrome:
Immaturity of the lungs will present this breathing problem from lack of surfactant. Naturally occurring, surfactants are substances that keep the lungs inflated and help prevent the air sacs in the lungs from collapsing. Some preemies may experience prolonged pauses in their breathing, known as apnoea.
· Heart problems: The most common problems are patent ductus arteriosus (PDA) and low blood pressure (hypotension). PDA is a persistent opening between two major blood vessels leading from the heart. This heart defect often closes on its own. Left untreated, it can cause heart failure and other complications.
· Temperature control: Preemies can lose body heat rapidly; they don't have enough stored body fat of a full-term infant to keep warm. Smaller preemies require additional heat from a warmer or an incubator until they are larger and able to maintain body temperature without help.
· Brain haemorrhage: The less developed blood vessels in the baby’s brain are delicate and more likely to break and bleed. The baby may show slow reflexes, weak suction of the mouth, fits and apnoea. Most bleeding episodes are mild and resolve with little short-term impact. But some babies may have larger bleeding resulting in permanent brain injury.
· Intestinal inflammation: Preemies are more likely to have immature gastrointestinal systems, leaving them more prone to intestinal inflammation. Occasionally, serious complications such as necrotizing enterocolitis (NEC) in which the cells lining the intestine wall are injured, can occur.
· Blood infection: Due to an underdeveloped immune system, preemies are more likely to get infection which can quickly spread to the bloodstream causing sepsis, a life-threatening complication.